Autostarter for induction motors



Sept. 13,1927. H E WHITE 4 ,0 1

AUTOSTARTER FOR INDUCTI ON MOTORS Filed May 25, 1925 3 Sheets-Sheet 1 WITNESSES: INVENTOR ATTORNEY Sept. 1 3,1927 1,642,001

H. E. WHITE AUTOSTARTER FOR INDUCTION MOTORS Filed May 2 L925 3 Sheets-Sheet 2 INVENTOR fiara/df h fiz'ie.

ATTORNEY WITNESSES:"

H. E. WHITE AUTOSTARTER FQR INDUCTION MOTORS Filed May 25, 1925 3 Sheets-Sheet 3 INVENTOR flare/a .E. h fi/fe.

I l 1 J WITNESSES;

ATTORNEY Patented Sept. 13, 1927.

i oniT-Eostares fen-tram; in FENCE.

THKROLD 1:. WHITE, or rnnns'rnvnnm, assrenon"'ro fwnsTING- noose. ELECTRIC & MANUFACTURING COMPANY, n CORPORATION 'O'F"PENNSYL VANIA.

, "enuros rianrnn ron innnosion Morons.

' lApplication' filed'May 25, 1325. Serial Nbfi325527.

rMy :invention relates to ='control apparatus and :it has :particular relation-to controllers -=for-starting alternating-current motors of --theinductiontype.

An object =of my iinvention iis to provide -a controller having manually operable starting and running switches .andyan electromagnetic line switch adapted 'to so make =and break the motor circuit as to avoid destnuctive arcing and burning ofzth'e switches.

Another object of my invention 1is to;p.ro- =vide mechanically operable interlocking means to insure the-openingof the electromagnetic line switch under predetermined conditions. i

Other objectsrof my invention will appear from ithe following description of my invention. y i 1 My invention will be described in connection with the accompanying drawings, in

which Fig. 1 is a :front view of a controller constructed inaccordance with my invention.

Fig. 2 isa sidebview of the controller illustrated in Fig. 1.

Fig. 3 is a side view of the controller illustrated in Fig. 1, showing details of the line switch and interlocking mechanism, and Fig. 4 is-a diagrammatic vie-w of circuits and apparatus embodying-my invention@ My invention finds particular application in connection with controlling mechanisms, such as autoistarters of the type illustrated and described Fin Patent No. 1.430589 of V. S. Roberts and C. 'H. I-Iodgkins, dated October 3. 1922, and assigned to the "West inghouse Electric and Manufacturing Company.

Referring particularly to Figs. 1 and 2, the controlling mechanism comprises a casing' having an :upper stationary part2 that is adapted to be secured to any suit-able support and a lower tank or casing 3 for enclosing the switching mechanism.

The switching mechnism comprises two rows of stationary contact members 7 that are mounted upon, and insulated from, sup porting bars 8. Acorresponding number of pairs of oppositely disposed movable contact members 9 are mounted upon, and insulated'from, a rock shaft 10. The respective contact members 9 are pivotally mounted upon bearing pins 11 and the members of reach pair are yielding ly retained in the relative positions, illustrated in Fig.2, by means iof springs 12.. The :le-ft-handpswitch members,illustrated :in Fig. 2, comprise a i-pole starting switch 13,. and the righthand wmem'bers .comprise'ra 2-pole running switch 14 (Fig. 4); y l v The switching mechanism is operated by a lever 17 that'wis located. outside the casing and is connected to the rock shaft 10. This operating lever and the switching mechanismare normally biased to an inoperative position'bya centering device :21, whichicomip'risesa afsta-tionary pin 22 r and'itwooppositely disposed arms 23 that resemble a :pair of calipers. The arms 23 are :pivotally supported by the shaft 10. and bear against thepin 22in the off position.

A centerinr; tension spring 24 :is connected between the arms 23 to resist theseparation of said arms when the lever 17 is "actuated in either direction from the neutral position. i A 'pin'or stop-member 25 is mounted upon an arm 26 that is secured-to the shaft 10 and is adapted to stress the centering spring- 24. The controller is :pro vidfed with ZID ELHtLVlbI'fltlOII catch 30. similar in character to that described in the above-mentioned patent. Detailed description-of this device is believed to be unnecessary and it forms no part of my invention. e

Referringto Figs. 1 and 3, the electromagneticlineswitch embodies a. pair of stationary ;contact members 31 and cooperating movable contact- -members 32. The movable contact members 32 are rotatably mounted upon, and insulated from, the rock shaft 10. A magnet armature '33 is pivotally, mounted upon a bearing. pin 34 and connected, through a link member 35, for operating the movable switch member 32. The armature 33 is controlled in a familiar manner by -means comprising an operating coil 36. A lever 37 is fixed upon the shaft l0 and is flexibly connected. throughsprin'gs 38, to operate a lever 39, which is rotatably mounted on-the shaft 10 and is adapted to mechanically interlock with the armature 33. For this purpose, armature 33 is provided with a lower extension ortail piece, carrying a roller 41.

Referring to Figs.=-1 and 4, an auxiliary switch 42, commonly termed "an electrical interlock, is'actua'ted in accordance with the movement of the controller-operating lever 17 for controlling the "energization of the line-switch coil 36. The interlock 42 is of a familiar spring-closed type and is opened in the off. position of the controller by a cam member 43. Within the controller casing are mounted, in a familiar manner, the auto-transformer 44 and an overload relay 45.

When the rock shaft 10 is rotated in a clockwise direction, the left-hand contact members 7 and 9 are engaged to set up the motor-starting circuits. The starting circuits, however, are not completed until the line-switch contact members 31 and 32 are closed. When the .rock shaft 10 is rotated to starting position, the lever 39 occupies the dotted-line position b, and interlock 42 .closes to effect the energization of line switch coil 36. The movable switch member 32 is closed by armature 33 to complete the'mo .tor starting connections.

Referring to the diagram of connections, Fig. 4, the auto-transformer coils 51 and 52 are energized from a source of supply comprising conductors 53, 54, 55 and 56. A circuit for coil 51 extends from line conductor 56, through the upper movable contact member 32, conductor 57, starting switch 13, coil 51, conductor- 58 and switch 13, to line conductor 54. Similarly, a circuit for coil 52 extends from line conductor 55, through lower line switch member 32, conductor 59, starting switch '13, coil 52, conductor 60, and switch 13, to line conductor 53. A reduced voltage is, therefore, applied to the motor, which in accordance with a familiar practice, is connected to transformer-winding-taps and, when the motor has started, the shaft'10 should be rotated in a reversed or counterclockwise direction, whereupon interlock 42 is opened to de-energize the lineswitch coil 36.

The lever 39 is carried from the starting position 6 toward the running position 0, thereby engaging roller 41 and insur ing the openingof line-switch contact members 32 prior to the closure of the running switch 14, which is actuated, as indicated in V Fig. 2, upon a counterclockwise rotation of rock shaft 10. The interlock 42 is again closedin the running position to re-energize coil 36, so that the line switch contact members 32 close subsequently to the closure of the running switches.

When lever 39 (Fig. 3) occupies the dotted line position 0, the controller is latched in the running position, since the armature 33 is closed and the roller 41 engages the right-hand side of the lever 39.

hen the controller is actuated to its off position the rock shaft 10 is operated in a clockwise direction by means of lever 17, but this motion is resisted by the action of the tension springs 38, which are stressed by the movement of lever 37 which is actuated by the rock shaft 10. During a part of the movement toward the off position,

lever 39 is retained in position a, being latched in position by means of the roller 41. In this manner, considerable pressure is brought to bear against the armature 33, in opposition to the action of the coil 36. After a suitable angular movement of lever 37, and a Corresponding angular movement of the interlock cam 43, the interlock 42 is opened to de-energize coil 36; and switch members 32 are thereupon opened with a snap-action that is occasioned by the mechanical interlocking of the members 39 and 41 and the tension of springs 38. Thesprings 38 are preferably of such strength as to resist the movement of the controller to the ofl position prior to the opening of lineswitch members32. That is to say, a slight movement of the operating lever 17 toward the off position insures the opening of the line switch prior to the opening of the running switches.

It will also be apparent that, in the event of overload or upon a failure of voltage, coil 36 will become de-energized and permit the controller to return automatically to its off position by reason of the action of the centering device 21 and independently of the normal manual operation of the controller.

From the foregoing description of the operation of the controller, it will be apparent that the making and breaking of the motor circuit is effected through the operation of an electromagnetic line switch and mechanism associated therewith for insuring a quick opening and closing of the motor circuit to prevent such destructive arcing at the switch members as is present in many manually operable controllers, especially when manipulated by inexperienced operators. I have illustrated my invention in one form for which it is peculiarly adapted, namely, in connection with auto-starters; however, I desire that it shall not be limited to the precise structure described but only in accordance with the scope of the appended claims.

I claim as my invention:

1. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, and means for insuring the closure of the line switch subsequent to the closure of the start ing switches and for insuring the opening of said line switch prior to the closure of said running switches.

2. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, means for insuring the closure of the line switch subsequent to the closure of the starting switches and for insuring the opening of said line loo operable means for insuring the opening of said line switch.

4. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, means for insuring the closure of the line switch subsequent to the closure of the starting switches, means for effecting the demagnetization of said line switch and mechanically operable yielding means for insuring a snapaction opening movement of said line switch when the starter is operated to its inoperative position.

5. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, means for insuring the closure of the line switch subsequent to the closure of the starting switches, means for effecting the demagnetization of said line switch and mechanically operable means for insuring the opening of said line switch prior to the opening of the starting and running switches, respectively.

6. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, means for insuring the closure of the line switch subsequent to the closure of the starting switches and means comprising the line switch magnet for holding said running switches closed.

7. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, means for insuring the closure of the line switch subsequent to the closure of the starting switches and for insuring the opening of said line switch prior to the closure of said running switches, and holding means for said running switches comprising the line switch magnet.

8. In a motor starter, the combination with a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, means for insuring the closure of the line switch subsequent to the closure of the starting switches and a single electro-responsive means for rendering said line and running switches effective. a

9. In a motor starter, the combination ith a plurality of starting and running switches and actuating means therefor, of a magnetically operable line switch, and means comprising the line switch magnet for also controlling said running switch.

10. In an autostarter, the combination with a plurality of starting and running switches and manually operable means for actuating said members, of a magnetically operable line-switch, an electrical interlock operable with said starting and running switches for controlling said line switch, means for opening said line switch when deenergized, and biasing means associated with said interlock for effecting a quick opening of said line switch.

ll. In an autostarter, the combination with a plurality of starting and running switches and manually operable means for actuating said members, of a magnetically operable line-switch, an electrical interlock operable with said starting and running switches for controlling said line switch, spring actuated means for opening said line switch when deenergized, and biasing means comprising a link mechanism operable with said interlock for effecting a quick opening of said line switch.

12. In an autostarter, the combination with a plurality of starting and running switches and a manually operable rock-shaft therefor, of a magnetically operable lineswitch, an electrical-interlock operated by said rock-shaft for controlling said lineswitch, a centering-spring device for restoring said rock-shaft, a cam member rotatably mounted on said rock-shaft for operating said line switch, and a yielding connection between said rock-shaft and said cam comprising a lost motion device, whereby said cam becomes effective to stress said line switch toward its open position prior to the operation of said interlock.

In testimony whereof, I have hereunto subscribed my name this 13th day of May,

HAROLD E. WHITE. 

